Question

i think he's still in ()bed,but he might just be in (the )ba

Answer 1

定冠词the是特指某样事物,指明了其对象.而且but是转折

i think he's still in bed,but he might just be in the bathroom.

这句话就强调他在那个卧室,可能不仍然在本来的床上（卧室里有两张床）.

i think he's still in the bed,but he might just be in bathroom.

这样就强调了他仍然在原来的床上,但或许不在同一卧室.

如果前后没有the,句子就没有中心.

个人理解-x-